Milking systems comprising rotary platforms are known in the art. In such a milking system, animals stand on the rotary platform while they are being milked. A rotary encoder is connected to the rotary platform. The rotary encoder may be used e.g. for controlling a speed of the platform, keeping track of a position of the platform, and/or indexing the platform. The milking system may be fully automatic, i.e. teat cups of the milking system are attached automatically to the teats of the animals, or the teat cups may be attached manually to the teats of the animals.
US 2011/308467 discloses a system and a method for controlling the speed of a rotary milking platform using a rotary encoder. In FIG. 1C the rotary encoder is illustrated. The rotary encoder includes an electromechanical device operable to convert an angular position of a shaft into an electrical signal. The rotary encoder comprises the shaft to which a rotary encoder wheel is coupled. The rotary encoder wheel abuts against the platform and is thus rotated by the platform when the platform rotates.
As illustrated herein in FIG. 1, the rotary encoder of US 2011/308467 is attached to an arm (A) which is pivotable about a vertical axis (B). Thus, the shaft of the rotary encoder and the vertical axis are substantially parallel. The arm and the rotary encoder are pivotably biased towards the rotary platform about the vertical axis. The arm is arranged at an acute angle to the periphery of the rotary platform. The force acting on the rotary encoder wheel and the rotary encoder thus, will differ depending on the direction of rotation of the rotary platform. This may lead to strain on the shaft and/or encoding errors in the rotary encoder. Moreover, encoding errors may be caused by unevenness of the rotary milking platform or an oval shape of the rotary milking platform since a pivoting of the arm about the vertical axis (B), with the rotary encoder wheel in contact with the rotary platform will rotate the shaft of the encoder.